I have so many favourite easter eggs from batman films, but my favourite has to be the Riddler graffiti in Batman V Superman: Dawn of Justice. It was in one of the big fight scenes, there's more about it in this article if you're interested.
I noticed a few things in Suicide Squad too, what about everyone else? I want to know all the easter eggs, what are the best?

here are a few more interesting ones: http://screenrant.com/secrets-hidden-in-dc-movies/